Illustrations paragraph 7
The same applies to telling the bridegroom about the father-in-law. If the bride has a indiscernable internal disease and the bridegroom would not agree to the marriage if he knew of it, one may tell him if the conditions are fulfilled. The same applies if the father-in-law’s home is immodest, which is great reason for the purpose of marriage to be destroyed. However, one should consider whether the bridegroom will listen to him, for it often happens that he will not and telling him only leads to rechilus.